JPH01155197A - Fin tube type heat exchanger - Google Patents

Abstract

PURPOSE:To promote turbulent flow as well as the leading edge effect of boundary layer and improve heat transfer coefficient, by a method wherein a plate fin is provided with cut-and-raised parts, opened in airflow, between heat transfer tubes while the configuration, the number and the like of the cut-and-raised parts are specified. CONSTITUTION:Cut-and raised parts 14a-14c, opened in airflow B, are provided on a plate fin 11 between heat transfer tubes 13 by a method wherein a flat base board is set on the center line of a plate fin 11 between the heat transfer tubes 13 and leg parts 15a-15c, whereat the cut-and-raised parts 14a-14c are connected to the plate fin 11, are provided alternately in up-and-down direction so as to pinch the base board of the plate fin 11 and have a certain angle between the direction of a normal line of the leading edge of the plate fin 11 while the number of the cut-and-raised parts 14a-14c is increased from the center between the heat transfer tubes 13 toward the end of the plate fin 11 and the height (h) of the cut-and-raised part is formed so as to be 1/2 substantially of the pitch Pf of the plate fin 11. The leading edge effect of boundary layer and the efficiency of the fin may be improved by the method above- described while turbulent flow may be promoted and heat transfer performance may be improved.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a fin-tube heat exchanger used in cooling systems such as air conditioners and refrigerators, which transfers heat between a refrigerant and a fluid such as air. be.

BACKGROUND OF THE INVENTION In recent years, as air conditioning equipment has become smaller and thinner, there has been a demand for improved performance of fin-tube heat exchangers, which are their constituent parts.

Hereinafter, an example of a conventional fin-tube heat exchanger will be explained in detail with reference to the drawings. Figure 3.

FIG. 4 shows a conventional fin-tube heat exchanger.

! Part 1 is a plate-shaped fin, with fin collars 2 raised at equal intervals, and a cut-and-raised part 1a opened toward the airflow A between the fin collars 2 from the substrate only on the fin collar 2 side of the plate-shaped fin 1. They are formed with the same height. The cut and raised portions 1a are for preventing the development of a temperature boundary layer. Reference numeral 3 denotes a heat transfer tube, which is inserted through the plate-shaped fin 1, expanded, and brought into close contact with the inner surface of the fin collar 2. The heat exchanger tube 3 is formed in a U-shape, and both ends thereof are connected by a bend. 4a and 4b indicate dead areas formed on the downstream side of the heat exchanger tubes 3.

Problems to be Solved by the Invention However, in the above configuration, the cut and raised portions 1a are not provided between the heat exchanger tubes 3 with the base portion left in the direction perpendicular to the airflow A.
The average heat conduction distance from the front and back is long, resulting in poor fin efficiency. Further, the leading edge distance of the cut and raised portion 1a is short, and the leading edge effect of the boundary layer is small. In addition, if the legs of the raised cut 1a are aligned with the normal direction of the front edge of the plate-like fin 1, the direction of the airflow does not change even after passing the raised cut 1a, and turbulence cannot be promoted. If the dead areas 4a, 4b are large, the effective heat transfer area will decrease. Furthermore, since the legs of the cut and raised portions 1a are lined up in front and behind with respect to the air inflow direction, resistance to the flow is concentrated, and the flow velocity distribution is non-uniform. As a result, the effect of the cut and raised portion 1a is not fully utilized.

Furthermore, since there is a raised cut 1a on the center line between the heat exchanger tubes 3 of the plate-shaped fin 1, when the condensed water is used as an evaporator, when the condensed water flows downward to the heat exchanger tubes 3 at γa, this cut and raised 1a prevents it from flowing smoothly. air resistance increases. Furthermore, the condensed water covers the cut-and-raised portion 1a, making it impossible to utilize the effect of the cut-and-raised portion.

Therefore, in view of the above-mentioned problems, the present invention increases the mJ edge rough distance of cutting and raising, increases the boundary layer 01J edge effect, and does not reduce the fin efficiency. In addition, by promoting turbulence and directing the airflow to the downstream side of the heat transfer tube, dead areas are reduced and the effective heat transfer area is increased. Furthermore, by dispersing the resistance to the flow, the speed of the airflow is made uniform between the heat transfer tubes and between the adjacent plate-like fins, and the turbulence caused by cutting and raising is promoted and the old edge effect of the boundary layer is increased. Another object of the present invention is to provide a high-performance fin-tube heat exchanger that does not increase air resistance even when used as an evaporator and has significantly improved heat transfer coefficient.

Means for Solving the Problems In order to solve the above problems, the present invention includes plate-like fins that include:
The cut-and-raised plate-like fins with openings to the air flow between the heat transfer tubes are placed on a flat base on the center line between the heat-transfer tubes of the plate-like fins, and the bases of the plate-like fins are sandwiched between the plate-like fins, alternating up and down. The legs to be joined to the plate fins are provided so as to form an angle with the normal direction of the front edge of the plate fin, and the number of cut and raised portions is arranged sequentially from the center between the heat transfer tubes of the plate fin toward the end of the plate fin. The leg portions are formed so that they do not overlap at the front and rear in the airflow direction, and the cut-up height h is approximately 1/2 of the pitch PH of the plate-like fins.

Functions Since the present invention has the above configuration, it has the following functions.

The cut and raised sections are placed between the heat exchanger tubes, leaving the base in the direction perpendicular to the airflow A, and even though there are many cut and raised legs and the leading edge distance is long, the average heat conduction distance from the front and back of the heat exchanger tubes is also short. ) Fin efficiency is also improved. Since the leg that joins the cut-and-raised plate-shaped fin forms an angle with the normal direction of the front edge of the plate-shaped fin, a vortex is generated at this leg to promote turbulence, and the downstream side of the heat exchanger tube The dead area of the area decreases and the effective heat transfer area increases. Further, since the height h of the cut and raised portions is approximately 1/2 of the pitch Pf of the plate-like fins 11, the cut and raised portions are uniformly arranged between adjacent plate-like fins, and the airflow velocity becomes uniform. In addition, because the legs are formed so that they do not overlap in the front and back of the airflow direction, the generation of vortices at the legs is promoted without being affected by the upstream side, and the resistance to the flow is dispersed, so that there is no overlap between the heat exchanger tubes. The airflow velocity is also equalized.

Furthermore, since the plate-shaped fins have a flat base on the center line between the heat transfer tubes, when used as an evaporator, condensed water flows smoothly downward along the heat transfer tubes and does not accumulate on the cut edges, reducing air resistance. The effect of cutting and raising can be utilized without increasing the amount.

EXAMPLE Hereinafter, a fin-tube heat exchanger according to an example of the present invention will be described with reference to FIGS. 1 and 2. Numeral 11 is a plate-like fin, and fin collars 12 are raised at equal intervals. Reference numeral 13 denotes a heat transfer tube into which the plate-shaped fins 11 are inserted. The plate-like fins 11 have raised cut-outs 14 a , 14 b that are open to the airflow B between the heat transfer tubes 13 ,
14 , a flat base is placed on the center line between the heat exchanger tubes 13 of the plate-shaped fins 11, and the bases of the plate-shaped fins 11 are sandwiched between them, and the cut and raised portions 14a to 14 are cut and raised alternately up and down.
The leg portions 15a to 15a to which the plate fin 11 joins the plate fin 11 are provided so as to form an angle with the normal direction of the front edge of the plate fin 11, and the number of the cut and raised portions 14a to 14c is equal to the number of the plate fins 11. The cutting and raising height h is approximately 1/2 of the pitch P1 of the plate-like fins 11, and increases gradually from the center between the heat exchanger tubes 13 toward the ends of the plate-like fins 11.

1ea and 16b indicate dead areas generated on the downstream side of the heat exchanger tubes 13.

Next, the operation of the configuration of the embodiment will be explained.

The cut-and-raised parts 14a to 14b are formed by leaving the base of the plate-like fin 110 and increasing the number of pieces sequentially from the center to the ends of the plate-like fins by one, two, and three pieces, and are provided while leaving the base in the direction perpendicular to the airflow B. Legs 15 of the raised edges 14a to 14c
&~15c increases, the old edge distance becomes longer, and the average heat conduction distance from the front and back of the heat transfer tube 13 is shortened, improving the shift-in efficiency. Further, the leg portions 15a to 15C that are joined to the plate fins 11 of the cut and raised portions 14a to 14c are connected to the plate fins 11.
This leg 1 forms an angle with the normal direction of the leading edge of
Vortices are generated at 5a to 15c to promote turbulent flow. At the same time, the airflow B goes around to the downstream side of the heat transfer tube 13, so the dead area 1
6a and 16b can be reduced and the effective heat transfer area can be increased. In addition, since the cut-and-raised height h is approximately 1/2 of the pitch P of the plate-like fins 11, the cut-and-raised heights 14a to 14c are uniformly arranged between adjacent plate-like fins 11, and the speed of the airflow B is uniform. Nasi, cut up 1
The amount of air passing through 4a-140 is increased, and the boundary layer leading edge effect and turbulence promoting effect can be increased. Furthermore, since the legs 16a to 1eic are formed so that they do not overlap in the front and rear directions in the airflow B direction, the legs 16a to 1eic are
5a to 15a, the resistance to the flow is dispersed, and even between the heat exchanger tubes 13, the airflow B
speed is equalized. Furthermore, since the center line between the heat transfer tubes 13 of the plate-shaped fins 11 is a flat base,
Even when used as an evaporator, condensed water flows through the heat transfer tube 13.
Flows smoothly downward along the cut and raised lines 14a to 1
Since it does not accumulate at 4c, air resistance does not increase and the effect of cutting and raising 14a to 14° can be utilized.

Above all, the leading edge effect of the boundary layer improves fin efficiency.

The heat transfer performance of the heat exchanger, which can promote turbulence, reduce dead area, equalize air velocity, and reduce air resistance when using an evaporator, is significantly improved. Further, since the cut and raised portions 14a to 14c are multi-tiered leaving the base portion, the strength of the plate-like fin 11 is also improved.

Effects of the Invention As described above, the fin-tube heat exchanger of the present invention has a plurality of plate-shaped fins arranged in parallel at regular intervals and through which air flows, and a heat exchanger tube inserted through the plate-shaped fins at right angles. The plate-shaped fin has a raised cut-out opening to the airflow between the heat transfer tubes, and a flat base is placed on the center line between the heat transfer tubes of the plate-shaped fin, and the base of the plate-shaped fin is sandwiched between them. , the legs to be joined to the cut-and-raised plate-like fins are provided alternately up and down so that they form an angle with the normal direction of the front edge of the plate-like fin, and the number of cut-and-raised parts is set to the height between the heat transfer tubes of the plate-like fins. The leg portions are formed so as to increase sequentially from the center toward the ends of the plate-like fins so as not to overlap at the front and rear in the airflow direction, and the cut-up height h is approximately 1/2 of the pitch Pf of the plate-like fins. This has the following effects.

There are many cut and raised legs and the leading edge distance is long, which increases the leading edge effect of the boundary layer. In addition, the average heat conduction distance is shortened and fin efficiency is improved. A vortex is generated in the cut and raised legs, which promotes turbulence and at the same time reduces the dead area and increases the effective heat transfer area. Furthermore, the speed of airflow can be made uniform between adjacent plate-shaped fins and between adjacent heat transfer tubes, and the leading edge effect of the boundary layer and the effect of promoting turbulence can be increased. In addition, since the plate-shaped fins have a flat base on the center line between the heat transfer tubes, when used as an evaporator, condensed water flows smoothly along the heat transfer tubes and does not accumulate on the raised cutouts, reducing air resistance. The effect of cutting and raising can be utilized without increasing the size. In addition, a secondary effect of increasing the stiffness of the plate-like fins also occurs.

As a result of the above effects, heat transfer performance is dramatically improved, and a compact and high-performance fin-tube heat exchanger can be realized.

[Brief explanation of the drawing]

Fig. 1 is a partial side view showing a fin-tube heat exchanger according to an embodiment of the present invention, Fig. 2 is a sectional view taken along line DD' in Fig. 1, and Fig. 3 is a conventional fin-tube heat exchanger. FIG. 4 is a sectional view taken along line CC' in FIG. 3. 11... Plate fin, 13... Heat exchanger tube, 14a. 14 b, 14 c --- cut and raise, 15a,
16b. 15C...Legs, h...Cut-up height, P (...Pitch, B...Airflow.

Claims (4)

[Claims] (1) Consisting of a large number of plate-shaped fins arranged in parallel at regular intervals, through which air flows, and heat transfer tubes inserted at right angles to the plate-shaped fins. In between, cut and raised openings to the airflow are placed on a flat base on the center line between the heat transfer tubes of the plate-like fins, and the bases of the plate-like fins are sandwiched in between, and these cut-and-raised A fin-tube heat exchanger in which the number of plate-shaped fins is increased sequentially from the center between the heat transfer tubes toward the ends of the plate-shaped fins. (2) The fin-tube type heat sink according to claim 1, wherein the cut and raised portion is provided such that the leg portion that joins the cut and raised plate-like fin forms an angle with the normal direction of the front edge of the plate-like fin. exchanger. (3) The cut-up height h is the pitch P_f of the plate-shaped fin.
The fin-tube heat exchanger according to claim 1 or 2, wherein the heat exchanger is approximately 1/2 of the above. (4) The fin-tube heat exchanger according to claim 1, 2, or 3, wherein the legs joined to the cut-and-raised plate-like fins are formed so that they do not overlap in the front and rear directions in the airflow direction.